The Department of Radiology at UCSD has implemented a Small Animal Imaging Resource (SAIR) to support cancer research at UCSD and the San Diego bioresearch community. The SAIR is located in the vivarium at the Rebecca and John Moores UCSD Comprehensive Cancer Center (CC) on the La Jolla campus. This facility supports the efforts of the ICMIC investigators and the UCSD cancer research investigators and then Campus and city-wide efforts. Some non-UCSD potential users include: Sidney Kimmel CC, Scripps, Burnham and Salk Institutes, and the San Diego biotech companies. The UCSD SAIR will provide MRI, optical, CT, ultrasound, High-Resolution planar gamma imaging, and PET of rodents, as well as high-resolution digital autoradiography and fluorescent imaging of thin whole body rodent sections. Except for MRI, all modalities are at one site adjacent to the CC vivarium. Support and expertise includes optical imaging, animal support, image computation, MR & optical hardware and software, diagnostic agent chemistry, radiochemistry including a cyclotron, analytical chemistry, kinetic modeling, informatics, histology, and a vascularized solid tumor model to cost-effectively screen imaging paradigms. Our primary emphasis will be the acquisition of images for kinetic modeling. For this reason the kinetic modeling service will develop automated data reduction schemes. Our previous experience with the use of kinetic modeling for receptor density measurement from clinical studies has convinced us that the data reduction path from the image data set must be completely automated. There are two reasons for this: first is high throughput, and second and more important is the absence of operator intervention and the elimination of operator bias. This latter quality is essential for rigorous statistical analysis (by the ICMIC Biostatistics Service) of the imaging and biochemical/physiologic metrics. High-resolution ultrasound imaging will permit quantification of tumor size as well as measurement of left ventricular volume for recovery correction of PET sampled input functions. Most importantly, it will permit the use of in situ tumor models. A key contribution of ultrasound to cancer research in mice is the ability to image in sterile fashion and to do so without the need for anesthesia. This should permit frequent monitoring of tumor growth or regression following interventions. Members of the ICMIC Imaging Core will interact closely with colleagues of the Animal Models & Care and the IMCIC Biostatistics Service. Our goal will be the identification of the most effective imaging model and the efficient use of animals. This will be accomplished by weekly meetings of at least one member from each Core. These meetings will include: 1) meetings with new Pis to develop new imaging projects prior to composing new IACUC protocols, and 2) the review of completed IACUC protocols prior to IACUC submission.